<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>变量</title>
</head>
<body>
    
</body>
<script>
    var num1 = 070;  //八进制，等于十进制的56
    var num2 = 0x1f;  //十六进制，等于十进制的31
    console.log(num1,num2)
    //js保存的值不会无穷大，当数据超出时会转化成特殊的数据类型 Infinity
    console.log(isFinite(21));   //返回true
    console.log(isFinite("hello word"));   //返回false

</script>
</html>